We can help you better if you

can tell us more detail. I guess you are not in a program involving research, otherwise you don't need worry about fulltime status. You probably need to pay tuition, too.

Your advisor should be able to help you. When I was in school, my advisor was very helpful in solving all kinds of problem. If you think the ISO is doing something not right, your advisor can surely use his/her influence to force them to do what they should do -- that is, to help international students.